Nordkalk Oy Ab

Other

Fractivator Oy

Nordkalk Oyj Abp

Kautar Oy

Pentti Virtanen

Sakari Saastamoinen

The present invention relates to a method of manufacturing paper or cardboard, wherein paper or board pulp is diluted with an aqueous composition, which is formed from colloidal-size particles of carbonate and bicarbonate, and other states of carbonate in an aqueous solution, so that the pH in the aqueous solution remains essentially at a value of 6.0-8.3 during the formation, and water is removed from the pulp by draining, pressing, and drying. The invention also relates to a method of manufacturing the aqueous composition used for this purpose.

Use of acidic water in the manufacture of paper

The present invention relates to a process for manufacturing paper or board, wherein paper or board pulp is diluted with acidic water and wherein the pH value of the pulp is raised with an alkali simultaneously with increasing the solids content of the pulp by filtration, compression and evaporation on the wire, press and drying sections, and, at the same time, filler is precipitated from the acidic water into the paper or board structure. The invention also relates to moistening of paper or board, with a dry matter content of over 40%, in acidic water, after which the pH value is raised with an alkali, and the paper or board is dried, or it is dried after the moistening without raising the pH value.

Process for manufacturing paper or board

Method for the preparation of finely divided calcium hydroxide, where calcium oxide is comminuted in an impact disintegrator into which in addition to the calcium hydroxide a small amount of water is led to wet the particles obtained and to bind the dust. The calcium oxide powder is led to a conveyor being in connection with the impact disintegrator and operating as a pre-quencher, to which conveyer water is added and where the material is subjected to a kneading effect. The material which is a mixture of calcium oxide and calcium hydroxide is led from the conveyor to a cistern operating as post-quencher, to which cistern the remaining portion of the total water amount required for quenching is added. The amount of water added to the impact disintegrator and to the pre-quencher is altogether 20 . . . 50% of the total amount of water required for quenching, preferably about &#x2153; of the total amount of water required for quenching, and the amount of water added to the post-quencher is 80 . . . 50% of the total amount of water required for quenching, preferably about &#x2154; of the total amount of water required for quenching.

Method and apparatus for the preparation of finely divided calcium hydroxide

An impact mill equipped with transmission machinery () to rotate two coaxial rotors () of a rotor apparatus () by one single driving apparatus (). The transmission device includes, according to one alternative, a secondary shaft () equipped with a gear pair () or a conic gear (). The first gear () rotates a gear () at the shaft () of the first rotor (), and the second gear () rotates a gear () at the shaft () of the second rotor (), but in the opposite direction or at a different speed. The conic gear () rotates the gear () at the shaft () of the first rotor () in one direction, and the gear () at the shaft () of the second rotor () in the opposite direction.

Impact mill

The present invention relates to a porous fiber product, which contains chemical pulp or wood fibers, between which structural filler particles are attached, as well as to a method of manufacturing this product, wherein filler drops are produced in a spray dryer from the aqueous solution of the filler, the drops forming filler particles when the water evaporates, the particles being attached to the chemical pulp or wood fibers.

Reinforced porous fibre product

Method for producing an aqueous suspension, which is based on a hydraulic binder, and a hardened binder product. According to the invention, a composition of blending agents is added in the aqueous phase into the binder, which composition comprises calcium carbonate particles having an average particle size of 2-200 nm, in order to generate an aqueous suspension and, if needed, mineral fillers are added into this suspension, in order to produce a hardening plaster or concrete mixture. Besides calcium carbonate, the composition of blending agents can comprise calcium hydrogen carbonate and meta-kaolin sinter, too. By using the present invention, it is possible to improve the properties of products which are bound by hydraulic binders; with the described combination of blending agents it is possible to affect for instance the early strength, the frost resistance, the phenomenon of bleading, the plasticizing, the size of the transition zone and the durability of concrete or plaster, and to reduce the quantity of the hydraulic binder.

Aqueous suspension based on hydraulic binder and a process for the production thereof

Apparatus for the manufacture of a precast building element of concrete

A method and mould for manufacturing concrete elements by means of a turnable mould, whereby the concrete is cast in a main mould when the latter is in horizontal position while the mould is at the same time vibrated. The mould has a closed construction and is used in such a way that, at the casting stage, the second half of the mould construction, which is hinged in relation to the main mold, is in vertical position. Thereafter the mould construction is closed which causes a pressure on the concrete, whereby any excess concrete is extruded through the slit between the mould halves. Then the entire mould construction is turned into vertical position while continuing the vibration so as to eliminate any air that has moved to the outer surfaces of the element. The mould construction is turned further by 90.degree. so that said second half of the mould, which comprises a frame and an auxiliary mould fastened inside the frame, remains underneath. Finally the main mould is lifted into vertical position and the auxiliary mould is detached from the frame so as to shift the element away.

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Valkeakoski, Finland

Pentti Virtanen